The invention relates to an applicator that can be used for the local application of a liquid product to a person""s skin.
Personal use products such as antiperspirants, deodorants and cosmetics can be applied to a user""s skin in various forms by various devices. For example, deodorants and/or antiperspirants can be delivered as a spray from a pressurized container or a spray bottle, as a solid from a solid stick dispenser, or as a liquid from a roll-on applicator or a porous dome applicator.
In one aspect, the invention features, in general, an applicator for local application of a liquid to a person""s skin. The applicator includes a porous dome, a chamber under the dome, a squeeze bottle providing a reservoir containing the liquid, and a tube from the squeeze bottle to the chamber. The porous dome has pores sized to provide liquid transport therein by capillary action. The chamber provides a location for liquid in position to be transported into dome. Increased pressure in the reservoir from squeezing the bottle causes liquid to flow from the reservoir through the tube to the chamber, and decreased pressure in the reservoir from releasing the bottle causes excess liquid in the chamber to flow from the chamber through the tube to the reservoir.
In another aspect, the invention features, in general, an applicator for local application of a liquid to a person""s skin that includes a porous dome, a squeeze bottle providing a reservoir containing the liquid, and a tube to convey liquid from the squeeze bottle to the dome. The bottle is made of a relatively rigid plastic (e.g., polyethylene terephthalate) and includes a relatively rigid, molded open-end portion connected to the dome and an integral flexible, blow-molded reservoir portion that can be squeezed to a reduced volume condition to deliver liquid to the dome and has a memory to return to an unsqueezed volume condition.
Particular embodiments of the invention may include one or more of the following features. The applicator can include a valve operable to block flow through the tube, and a cap that causes the valve to be closed when the cap is connected to the squeeze bottle. The applicator can include a dome adapter located between the squeeze bottle and the porous dome, such that the chamber providing liquid to the porous dome is defined by the dome adapter and the porous dome. The dome adapter can have a central passage and a valve structure at the bottom of the central passage, the valve structure being in fluid communication with the tube. A collar can be used to connect the dome adapter to the porous dome. The applicator can include a bottle adapter connected to the bottle, with the porous dome being movably mounted with respect to the bottle adapter. The collar can be slidably mounted with respect to the bottle adapter. The bottle adapter can have a central portion that is sealably connected to the tube and has an opening in communication with the tube. The applicator can have a spring between the bottle adapter and the dome adapter that biases the valve structure away from the opening. The dome adapter can include a sliding seal with the bottle adapter around the opening. The bottle adapter can snap onto the squeeze bottle.
The chamber and porous dome are preferably dimensioned and shaped so as to provide preferential blooming of the liquid at the center of the dome first and subsequent blooming of liquid closer to the periphery of the dome. The chamber and dome are also dimensioned and shaped so that, when the user releases the squeeze bottle, excess liquid on the top of the dome is pulled back into the applicator, and is preferentially first removed from the peripheral portions and then from the central portion. The chamber can have a central volume area that communicates with the tube, a peripheral volume area, and a constricted region connecting the central volume area to the peripheral volume area to provide the preferential blooming. The porous dome has a stepped recess surface with a central recess that provides the central volume area and a peripheral recess that provides the peripheral volume area.
The porous dome is preferably made of sintered plastic, e.g., sintered high-density polyethylene, and preferably is made of round particles to provide a smooth surface for contacting the skin. The sintered plastic has an average pore size between 10 and 30 microns, preferably around 18 microns.
Embodiments of the invention may include one or more of the following advantages. The applicator provides a uniform dose of liquid to the porous dome without large droplets on the dome surface or drips down the side of the applicator. A uniform, thin layer of liquid is applied to the user""s skin surface without irritation. The applicator does not leak liquid, and is easy to manufacture.
Other features and advantages of the invention will be apparent from the following detailed description of a particular embodiment thereof and from the claims.